Surgical tool arrangement and surgical cutting accessory for use therewith

ABSTRACT

A surgical tool arrangement for performing endoscopic surgical procedures which includes a powered handpiece and a surgical cutting accessory which detachably connects to the handpiece. The cutting accessory incorporates a cutting head for resecting tissue and a suction arrangement at the distal end of the cutting accessory closely adjacent the cutting head which suction arrangement serves to evacuate tissue from the surgical site and additionally serves as a cleaning mechanism for the surgical cutting accessory. The accessory additionally incorporates a bearing arrangement for supporting the cutting element as same rotates within the housing element.

CROSS REFERENCE TO RELATED APPLICATION

This claims the benefit of U.S. Provisional Application Ser. No.62/064,719, filed Oct. 16, 2014.

FIELD OF THE INVENTION

This invention generally relates to a surgical tool arrangement usefulfor performing endoscopic surgical procedures which includes a poweredhandpiece and, more particularly, to a surgical cutting accessory whichdetachably connects to the handpiece and includes an outer housingelement and an inner cutting element with a cutting head for resectingtissue and a suction arrangement at the distal end of the cuttingaccessory closely adjacent the cutting head which suction arrangementevacuates surgical debris from the surgical site and also operates as acleaning mechanism for the cutting accessory to prevent buildup ofsurgical debris adjacent the cutting head. The accessory additionallyincorporates a bearing arrangement for supporting the cutting element assame rotates within the housing element.

BACKGROUND OF THE INVENTION

Endoscopic surgical procedures are routinely performed in order toaccomplish various surgical tasks. In such a surgical procedure, smallincisions or portals are made in the patient. An endoscope, which is adevice that allows medical personnel to view the surgical site, isinserted in one of the portals. Surgical instruments used to performother tasks are inserted into other portals. The surgeon views thesurgical site through the endoscope to determine how to manipulate thesurgical instruments in order to accomplish the desired procedure. Anadvantage of performing endoscopic surgery is that, since the portionsof the body that are cut open are minimized, the portions of the bodythat need to heal after the surgery are likewise reduced. Moreover,during an endoscopic surgical procedure, only relatively small portionsof the patient's internal organs and tissue are exposed to the openenvironment. This minimal opening of the patient's body lessens theextent to which the organs and tissue are open to infection.

The ability to perform endoscopic surgery is enhanced by the developmentof powered surgical tools especially designed to perform suchprocedures. Once such tool is sold by the assignee hereof under thetrademark FORMULA®. This tool is in the form of a cylindrical handpiecedesigned to be held in the hand of the surgeon. The handpiece has afront or distal end provided with a coupling assembly for releasablyholding a cutting accessory, and a motor disposed within a handpiecehousing which drives the accessory. The cutting accessories, such asshavers, drills and burs, include an outer housing element having a hubappropriately configured to cooperate with the coupling assembly of thehandpiece to lock the accessory thereto and an elongated housing tubehaving a proximal end fixed to the hub, and an inner cutting elementhaving a drive shaft disposed within the housing tube. When theaccessory is attached to the handpiece, the handpiece motor couples tothe drive shaft of the accessory and moves same relative to the housingtube. The handpiece motor is selectively actuable to drive the accessorydrive shaft so as to cause a desired cutting action at the distal end ofthe accessory. The handpiece is associated with a control unit whichcontrols the functioning thereof, and is actuated by the user viaappropriate buttons provided on the handpiece itself, at the controlunit or through use of a footswitch.

In an endoscopic surgical procedure, irrigating fluid is introduced intothe surgical site. This fluid serves as a transport media for removingtissue and debris from the surgical site. In order to remove theirrigating fluid and the material contained therein, the above handpieceand the various accessories which are usable therewith together define asuction conduit. A suction pump is connected to the handpiece to providethe suction force needed for drawing the fluid and material away fromthe surgical site. In order to control the suction flow through theaccessory and the handpiece, the handpiece is typically provided with amanually operated valve which is manipulated by the surgeon to controlsuction of material away from the surgical site.

Mechanical cutting accessories, such as the shaver, drill and burdiscussed above, are commonly used in arthroscopic procedures, and allowfor the resection of hard and soft bodily tissues, for example, thosefound within the knee, shoulder and other joints. A bur-type cuttingaccessory is sometimes used to resect bone or other hard tissues, andincludes a cutting head with cutting features which when rotated serveto cut away targeted bone or hard tissue. Such cutting features mayinclude straight or helically-oriented cutting edges which extendlongitudinally along the cutting head of the bur. Another bur-typecutting accessory is a diamond bur which includes diamond particles ascutting features which are embedded in a metal surface of the cuttinghead. Such bur-type cutting accessories often have solid cutting headsso as to have sufficient strength for abrading or cutting hard tissue. Abur-type cutting accessory includes a cutting head with cutting featuressuch as those described above which are exposed through a window formedat the distal end of the outer housing element when the cutting elementis located therein. In some bur-type cutting accessories, the windowformed in the outer housing element opens primarily sidewardly, so thatthe distal end of the outer housing element covers a portion or one sideof the cutting features of the cutting head of the bur to allow the userto better target bone or hard tissue, and this type of configuration issometimes referred to as a “hooded” bur. Alternatively, the entiregeometry of the cutting head which defines the cutting features mayproject distally beyond the terminal end of the outer housing element,and this type of arrangement is often called “unhooded”. In a bur-typecutting accessory, as contrasted with a surgical shaver, the distal endof the outer housing element typically does not perform anytissue-cutting function, and serves essentially only to house andsupport the drive shaft of the inner cutting element and to shroud partof the cutting head thereof (in the case of a hooded arrangement), andthe cutting of hard tissue is carried out by the cutting features of thecutting head. In an unhooded bur configuration, the outer housingelement serves essentially only to house and support the drive shaft. Asdiscussed above, bur-type cutting accessories are typically used forremoval of particular bone or hard tissue types, and a variety ofdifferent bur geometries are available to specifically address the typeof cutting the accessory is to carry out.

Further, in one conventional bur-type cutting accessory, the cuttingelement includes an elongate and hollow tubular drive shaft and acutting head with cutting features is provided as a solid member whichis fixedly mounted to the distal end of the drive shaft. In order todraw suction through the cutting element in this type of accessory, asuction opening is provided at the distal end of the drive shaft. Thesuction opening opens sidewardly outwardly and communicates with thehollow interior of the drive shaft, and is located proximally of thecutting features of the cutting head. In operation, bone or other hardtissue removed or cut away by the cutting head is suctioned into thehollow interior of the drive shaft through the window of the outerhousing element and the suction opening. In this type of cuttingaccessory, it is possible that soft tissue can become wrapped around thecutting head in an area just proximal to the cutting features, which canblock suction through the suction opening, prevent evacuation ofsurgical debris, and result in the surgeon's field of view becomingoccluded. Such an occurrence will typically require that the surgeondisassemble the cutting accessory and manually unclog the suctionopening of the accessory before continuing with the surgery.

Additionally, the various types of surgical cutting accessories asdiscussed above typically require some type of bearing arrangement whichsupports the inner cutting element as same rotates within the outerhousing element. Such bearing arrangements may include one or morebushings or bearing sleeves provided on the inner cutting element whichserve to radially support the inner cutting element within the outerhousing element, and a thrust washer or spacer provided at the interfacebetween the mating proximal portions of the inner cutting element andouter housing element which serves to axially support the inner cuttingelement relative to the outer housing element. In some devices, thebearing sleeve which provides radial support is a heat-shrunk plasticsleeve applied to the exterior of the drive shaft of the inner cuttingelement. The bushings/bearing sleeves are typically provided as separatecomponents of the accessory, which can complicateassembly/manufacturing. Further, heat-shrunk plastic sleeves have a widetolerance range, which can make it difficult to maintain the desired gapbetween relatively movable components.

In an effort to obviate or at least minimize the disadvantages of knownsurgical accessories, a suction arrangement is provided which can beutilized to both evacuate surgical debris from the surgical site and toprovide a self-cleaning function for the cutting accessory. Further, abearing arrangement provides both radial and axial support for the innercutting element relative to the outer housing element. The bearingarrangement according to one embodiment is integrated into existingstructures of the surgical cutting accessory, and thus provides asimpler and more cost-effective design.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the surgical tool arrangement, includinga handpiece with a surgical accessory attached thereto;

FIG. 2 is an enlarged, fragmentary, longitudinal and cross-sectionalview of the handpiece of FIG. 1 with the surgical accessory attachedthereto;

FIG. 3 is a perspective view of the inner cutting element of thesurgical accessory;

FIG. 4 is a perspective view of the outer housing element of thesurgical accessory;

FIG. 5 is an enlarged and fragmentary top view of the distal end of theinner cutting element;

FIG. 6 is an enlarged and fragmentary view of the distal end of theinner cutting element rotated approximately 90 degrees from the positionshown in FIG. 5;

FIG. 7 is an enlarged and fragmentary top view of the surgicalaccessory;

FIG. 8 is an enlarged longitudinal cross-sectional view of the surgicalaccessory of FIG. 7, as seen generally along line VIII-VIII in FIG. 7;

FIG. 8A is an enlarged and fragmentary cross-sectional view of thesurgical accessory, as seen generally along line VIIIA-VIIIA in FIG. 8;

FIG. 8B is an enlarged perspective view of the hub of the inner cuttingelement in isolation;

FIG. 9 is an enlarged and fragmentary top view of the distal end of thesurgical accessory;

FIG. 10 is an enlarged cross-sectional view of the surgical accessory,as seen generally along line X-X in FIG. 9;

FIG. 11 is an enlarged cross-sectional view of the surgical accessory asseen generally along line XI-XI in FIG. 9;

FIG. 12 is an enlarged and fragmentary top view of the distal end of theinner cutting element of a second embodiment of the surgical accessory;

FIG. 13 is an enlarged and fragmentary view of the distal end of thesurgical accessory of the second embodiment with the inner cuttingelement rotated approximately 180 degrees from the position shown inFIG. 12;

FIG. 14 is an enlarged and fragmentary top view of the distal end of theinner cutting element of a third embodiment of the surgical accessory;

FIG. 15 is an enlarged and fragmentary view of the distal end of thesurgical accessory of the third embodiment with the inner cuttingelement rotated approximately 180 degrees from the position shown inFIG. 14;

FIG. 16 is an enlarged and fragmentary perspective view of the distalend of the inner cutting element of a fourth embodiment of the surgicalaccessory;

FIG. 17 is an enlarged and fragmentary perspective view of the distalend of the inner cutting element of the surgical accessory of the fourthembodiment, with the inner cutting element rotated approximately 90degrees from the position shown in FIG. 16;

FIG. 18 is an enlarged and fragmentary top view of the distal end of thesurgical accessory of the fourth embodiment;

FIG. 19 is an enlarged and fragmentary top view of the distal end of theinner cutting element of a fifth embodiment of the surgical accessory;

FIG. 20 is an enlarged and fragmentary view of the distal end of theinner cutting element of the fifth embodiment of the surgical accessory,with the inner cutting element rotated approximately 90 degrees from theposition shown in FIG. 19;

FIG. 21 is an enlarged and fragmentary view of the distal end of thesurgical accessory of the fifth embodiment.

FIG. 22 is an enlarged and fragmentary longitudinal cross-section of asixth embodiment of the surgical accessory; and

FIG. 23 is an enlarged perspective view of the hub, in isolation, of theinner cutting element of the sixth embodiment.

Certain terminology will be used in the following description forconvenience in reference only, and will not be limiting. For example,the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” willrefer to directions in the drawings to which reference is made. Thewords “inwardly” and “outwardly” will refer to directions toward andaway from, respectively, the geometric center of the arrangement anddesignated parts thereof. The words “forwardly” and “distally” willrefer to the direction toward the end of the arrangement which isclosest to the patient or which is first inserted into the patient, andthe words “rearwardly” and “proximally” will refer to the directiontoward the end of the arrangement which is furthest from the patient.Said terminology will include the words specifically mentioned,derivatives thereof, and words of similar import.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a surgical tool arrangement 10 isillustrated. The arrangement 10 includes a handpiece 11, which at itsdistal end mounts thereon a surgical accessory 12.

The handpiece 11 is a commercially available surgical handpiecemanufactured by the assignee hereof, under Model Nos. 375-704-500 and375-701-500, and is accordingly only briefly described herein. Thehandpiece 11 includes an elongate outer housing 13 defining an elongatebore 14 therein. A motor 15 (shown diagrammatically only in FIG. 1) isdisposed within the housing bore 14. The motor 15 includes an output ordrive shaft 16, which drive shaft 16 mounts a drive pin 17 at the distalend thereof. A power cable 18 is coupled to the proximal end of thehandpiece 11 for supplying power to the motor 15.

The handpiece housing 13 defines therein an elongate suction bore (notshown) extending generally parallel to and sidewardly of the housingbore 14. This suction bore communicates with a diagonally extendingsuction passage 20 defined in the housing 13, which passage 20 providescommunication between the distal end of the housing bore 14 and thesuction bore. Suction is drawn through the handpiece 11 by a suctionpump (not shown), which is connected to the handpiece 11 via a suctiontube 21. Suction flow through the handpiece 11 is regulated by anadjustable valve 22 having a valve stem (not shown) which is movablymounted in a valve bore 23 defined in the housing 13. The valve 22 isadjusted by the user via a movable handle or arm 24 connected to thevalve stem. The above handpiece suction arrangement is described indetail in U.S. Pat. No. 7,682,333 issued on Mar. 23, 2010, which patentis owned by the same assignee hereof and is hereby incorporated byreference herein in its entirety.

The accessory 12 is removably attached to the distal end of thehandpiece 11 by a coupling assembly 25 provided on the handpiece 11. Thecoupling assembly 25 includes a generally ring-shaped collet 26 securedto the distal end of the handpiece housing 13. A locking ring 27 ismovably disposed in the collet 26 and is biased to hold the accessory 12within the housing bore 14 of the handpiece 11. A release button 28 isprovided on the locking ring 27, and is used to release the locking ring27 and allow removal of the accessory 12 from the handpiece 11. Further,a coil 30 is provided in the collet 26, which is used to facilitateinductive signal transfer to/from a radio-frequency identificationdevice (RFID) disposed in the accessory 12 as discussed below.

Referring to FIGS. 3, 4 and 7-8B, the accessory 12 will now bedescribed. The accessory 12 defines a central longitudinal axis 31, andincludes an outer cannula or tubular housing element 32 and an innertubular cutting element 33 disposed within the housing element 32. Thehousing element 32 includes a hub 34 which defines the proximal endthereof. The hub 34 is defined by a generally tubular base body 35,which defines therein a plurality of generally rectangular openings 36adjacent the proximal end thereof which are distributed along thecircumference of the hub 34 (only two of which are shown in FIGS. 4 and7). The base body 35 also has formed thereon a pair ofoutwardly-projecting, diametrically opposed and generally ramp-shapedears 37 disposed distally of the openings 36. The ears 37 cooperate withthe coupling assembly 25 of the handpiece 11 to secure the accessory 12therein. The hub 34 has a distal end defined by a head or nose 39 of areduced diameter as compared to the base body 35. Further, the hub 34defines therein a bore 41 which opens through a distal end of the hub34. The bore 41 opens proximally into a counterbore 42 which opensproximally through a terminal end of the base body 35. The bore 41 andcounterbore 42 are joined to one another by a shoulder 43 which faces inthe proximal direction and extends transversely between the bores 41 and42. The openings 36 of the base body 35 communicate with bore 42.

An annular seal 45 is disposed within the proximal end of the bore 42 ofthe hub 34. With reference to FIGS. 2 and 8, the seal 45 is constructedof a resilient elastomeric material, and is defined by a main section 46and axially-spaced proximal and distal sections 47 and 48 disposed atrespective opposite ends of the main section 46. The proximal section 47defines thereon a pair of annular ribs 55 and 56, which are disposed insealing engagement with an inner annular surface of the collet 26 of thehandpiece 11 when the accessory 12 is coupled thereto, as shown in FIG.2. The distal section 48 defines thereon a plurality of outwardlyprojecting and diametrically-opposed lock tabs 57 which engage withinthe respective openings 36 of the hub 34 to secure the seal 45 to thehub 34 and fix the axial position of the seal 45 relative thereto. Thedistal section 48 additionally defines thereon a plurality of inwardlyprojecting and diametrically-opposed stop tabs 58, which are generallyradially aligned with the respective lock tabs 57. As shown in FIGS. 2,8 and 8A, an RFID device 59 encapsulated within a ring structure islocated within the hub bore 42 adjacent the distal section 48 of theseal 45.

The above-described coupling arrangement of the handpiece 11 and thearrangement of the encapsulated RFID device 59 and the coil 30 aredisclosed in U.S. Pat. No. 7,887,559 issued on Feb. 15, 2011, whichpatent is owned by the same assignee hereof and is hereby incorporatedby reference herein in its entirety.

The outer housing element 32 additionally includes an elongate housingtube 64 which projects distally from the hub 34 (see FIGS. 2, 4 and7-8A). The housing tube 64 has a proximal end 60 which is fixedlymounted within the bore 41 of the hub 34. The proximal end 60 of thehousing tube 64 in the illustrated embodiment is induction bonded to thehub 34 within the bore 41, which hub 34 has a large induction corethrough which the proximal end 60 extends via bore 41. In this regard,the proximal end 60 of the housing tube 64 may be knurled and/orchamfered so as to facilitate induction bonding of the proximal end 60to the hub 34. The proximal end 60 extends in the proximal directionaxially beyond the shoulder 43 of the hub 34 so as to have an exposedfree end 61 which extends into the hub bore 42. The housing tube 64defines an elongate bore or conduit 65 therein, in which the cuttingelement 33 is disposed as discussed below. The housing tube 64 has adistal end 66 which in the illustrated embodiment is cut so as to definea window 67 having an annular edge 68, which window 67 in theillustrated embodiment is made via an angled cut, resulting in a window67 which opens both sidewardly and distally of the tube 64.Alternatively, the distal end 66 of housing tube 64 may be cut in amanner such that the annular edge 68 is oriented perpendicular to theaxis 31. Other configurations of the distal end 66 of the housing tube64 may be provided, and the above are given only by way of example.

Turning now to the cutting element 33 (FIGS. 3 and 7-8B), same includesa hub 80 which defines the proximal end thereof. The hub 80 incorporatesa motor-engaging drive element 81 defining a proximally opening bore 82and slots 84, diametrically aligned pairs of which together define slotswhich extend transversely to the longitudinal axis 31 of the accessory12. The hub 80 additionally includes a neck 85 which projects distallyfrom the drive element 81. The neck 85 is joined to an enlarged head 86by an intermediate section 62. The head 86 defines the terminal distalpart of the hub 80. The outer diameter of the head 86 is slightly largerthan the inward projection of the respective stop tabs 58 of the seal45. A proximally oriented bore 87 opens through the proximal end of thehub 80 and extends axially through the neck 85 and a portion of theintermediate section 62, in which is fixed an elongate drive shaftassembly including a drive shaft 88. The drive shaft 88 defines thereina suction passage 89 which is in communication with a pair of suctionports 90 defined in neck 85, which suction ports 90 are in turn incommunication with the suction passage 20 of the handpiece 11. In theillustrated embodiment, the suction ports 90 open sidewardly from thehub 80. The proximally-oriented bore 87 opens distally into acounterbore 63 formed in the hub 80 which opens distally through thehead 86 thereof. The bore 87 and counterbore 63 are joined to oneanother by a shoulder 71 which faces in the distal direction and extendstransversely to the axis 31 between the bore 87 and the counterbore 63.In the illustrated embodiment, and with reference to FIGS. 8 and 8B, apair of channels 72 are provided diametrically opposite one anotherwithin the counterbore 63 and extend therealong. The channels 72 openradially inwardly and extend longitudinally from the shoulder 71 in thedistal direction and open distally through the head 86 of the hub 80.Further, each channel 72 opens radially outwardly via an opening 73which extends completely through the wall of the intermediate section 62of the hub 80.

With reference to FIGS. 3, 5, 6 and 8, the drive shaft assembly includesa cutting head 104. In the illustrated embodiment, the drive shaft 88and the cutting head 104 of the drive shaft assembly are constructed asseparate components which are fixed to one another. In this regard, thedrive shaft 88 may be constructed of a rigid plastic and a distal end 91thereof induction welded to the cutting head 104, which may beconstructed of rigid metal, such as stainless steel. Alternatively, thedrive shaft 88 and the cutting head 104 may be constructed as anintegral or one-piece member formed from rigid metal, such as stainlesssteel. The cutting head 104 is generally cylindrical and partiallytubular in the illustrated embodiment as discussed below.

As best shown in FIGS. 5, 6 and 10, the cutting head 104 includes atubular proximal end 106 of a generally constant diameter and which inthe illustrated embodiment is fixed to the distal end 91 of the driveshaft 88, a tubular neck portion 107 extending distally from theproximal end 106 and a distal end 109 which extends distally from aconical distal end 108 of the neck portion 107. The majority of the neckportion 107 has an enlarged outer diameter as compared to the outerdiameter of the proximal end 106. Where the neck portion 107 adjoins theproximal end 106, the neck portion 107 tapers gradually outwardly awayfrom the axis 31 of the surgical accessory 12 as the neck portion 107projects away from the proximal end 106. The proximal end 106 and theneck portion 107 are each defined by respective walls 110 and 111, theinner surfaces of which walls 110, 111 together define a suction passage112 which extends proximally from the distal end 109 of the cutting head104 and opens through the proximal end 106 for communication with thesuction passage 89 of the drive shaft 88.

The distal end 109 of the cutting head 104 is configured for cuttingbodily tissue and has a configuration of what is commonly considered abur. The distal end 109 is generally cylindrical and defines an exteriorsurface 113 having formed thereon a plurality of cutting features, suchas cutting edges 114. In the illustrated embodiment, and as shown inFIGS. 8 and 10, the distal end 109 is a solid member. The cutting edges114 project outwardly from the exterior surface 113 in a direction awayfrom the axis 31, and in the illustrated embodiment additionally extendin a helical manner about the axis 31 along the longitudinal extent ofthe distal end 109 and in a generally parallel manner with one anotheralong a majority of the longitudinal extent of the distal end 109. Thecutting edges 114 extend gradually towards one another in the proximalto distal direction and terminate adjacent a tip 117 of the distal end109. A flute or groove 118 is defined between each adjacent pair ofcutting edges 114, which grooves 118 extend helically about the axis 31along the distal end 109. It will be appreciated that the cutting edges114 may alternatively be non-helical or substantially straight so as toextend generally parallel with the axis 31 or so as to be oriented at anangle relative to the axis 31. The respective grooves/flutes 118 in thisembodiment would thus also be substantially straight. Further, thenumber of cutting edges 114 will vary depending upon the dimensions ofthe cutting head 104 and/or the type of cutting action desired, and theconfiguration of the cutting edges 114 as disclosed herein is presentedonly as an example of one suitable configuration for cutting edges of acutting head 104.

Referring to FIGS. 9 and 10, the wall 111 of the tubular neck portion107 has an outer surface 120 with an outer diameter which is greaterthan an outer diameter of the distal end or bur 109 and slightly smallerthan the inner diameter of the housing tube 64. Further, theconfiguration or contour of the outer surface 120 is similar to orsubstantially conforms to the contour of an inner surface 121 of thehousing tube 64. The outer surface 120 thus serves as a bearing surfacevia its engagement with the inner surface 121 of the housing tube 64.The cooperation between the inner surface 121 and the outer surface 120forms a distal bearing for rotatably supporting the drive shaft 88within the housing tube at the distal end of the surgical accessory 12.

The wall 111 of the tubular neck portion 107 defines a suction openingtherein which opens outwardly through the bearing surface 120, and inthe illustrated embodiment, a plurality of such suction openings 122 and123 are provided within the wall 111 which open outwardly through thebearing surface 120. The suction openings 122 and 123 are oriented incircumferentially spaced-apart relation with one another about the neckportion 107. In the illustrated embodiment, the suction openings 122 and123 are spaced at approximately 90 degree intervals from one anotheralong the circumference of the neck portion 107, and two of the suctionopenings 122 are located diametrically opposite one another(approximately 180 degrees from one another), are axially aligned withone another, and are located closer to the distal end or bur 109 thanthe remaining two suction openings 123. The remaining two suctionopenings 123, or proximal suction openings 123, are axially aligned withone another and are diametrically opposite one another on the neckportion 107. Each of the suction openings 122 and 123 extends completelythrough the wall 111 for communication with the suction passage 112 ofthe cutting head 104 and the suction passage 89 of the drive shaft 88,and in the illustrated embodiment each suction opening 122, 123 has acircular configuration.

As best shown in FIGS. 10 and 11, the placement of the suction openings122 and 123 in the bearing surface 120 positions the openings 122 and123 in close, face-to-face or opposed relationship (in a radialdirection relative to the axis 31) with the inner surface 121 of thehousing tube 64. Further, each of the suction openings 122 and 123 has apair of opposed edges 132 and 130 (see FIGS. 5, 6 and 11) adjacent thebearing surface 120 of the neck portion 107 which edges, when the innercutting element 33 is rotated inside the outer housing element 32, arepositioned in circumferentially opposed relation with the adjacent edge68 of the housing element window 67 as discussed further below. Theseedges 130 and 132 can be provided with a blunt or non-acuteconfiguration, a chamfered edge configuration suitable fornon-aggressive cutting or resection of tissue such as the edgeconfiguration shown in FIG. 11, or a sharp or acute edge configurationsuitable for more aggressive cutting of tissue.

The inner cutting element 33 is assembled to the outer tubular housingelement 32 by inserting the distal end 109 of the cutting element 33into the proximal end of the bore 42 of the hub 34. During thisinsertion, the enlarged head 86 of the hub 80 expands the seal 45 andthe head 86 pushes past the stop tabs 58, at which point the seal 45essentially resumes its original shape. The stop tabs 58, while allowingsome axial displacement of the cutting element 33 relative to housingelement 32, prevent the cutting element 33 from detaching or falling outof the housing element 32 due to gravitational forces. When the cuttingelement 33 is fully inserted into the housing element 32, the free end61 of the housing tube 64 extends in the proximal direction into thecounterbore 63 of the hub 80 and abuts against the shoulder 71, as bestshown in FIG. 8A. The wall of the hub 80 which defines the counterbore63 has an inner surface 74 with a diameter which is similar to, butslightly larger than, the outer diameter of the free end 61 of thehousing tube 64, such that there is only a small radial clearancebetween the free end 61 and the inner surface 74. The engagement of theouter surface of the free end 61 of the housing tube 64 with the innersurface 74, and the abutting engagement of the free end 61 of thehousing tube 64 with the shoulder 71, provides a radial bearing and anaxial bearing, respectively, at the proximal end of the surgicalaccessory 12. As discussed further below, when the accessory 12 ismounted to the handpiece 11, a spring 75 provided within the driveelement 81 of the cutting element 33 cooperates with the handpiece 11and biases the cutting element 33 axially in the distal directionrelative to the outer housing element 32, which serves to maintain thefree or terminal end 61 of the housing tube 64 axially against theshoulder 71.

The mating areas between the inner surface 74 of the hub 80 and theouter surface of the free end 61 of the housing tube 64 can be providedwith lubricant in order to minimize friction between these componentsduring movement of the inner cutting element 33 relative to the outerhousing element 32. In this regard, and as best shown in FIGS. 8 and 8B,lubricant can be applied to the counterbore 63 through the openings 73and/or through the distally opening areas of the channels 72, so thatthe lubricant will enter the channels 72 and lubricate between the freeend 61 of the housing tube 64 and the hub 80.

The assembled accessory 12 is secured to the handpiece 11 in a similarmanner to that described in the '559 patent referenced above, and thisassembly will accordingly be only briefly described here. The accessory12 is attached to handpiece 11 by inserting the hubs 34 and 80 into theopen distal end of the collet 26. The ears 37 of the hub 34 seat withinthe collet 26, and the locking ring 27 serves to hold the accessory 12within the handpiece 11. The above securement of the accessory 12 to thehandpiece 11 causes the drive element 81 of the accessory 12 to engagethe motor output shaft 16 of the handpiece 11. More specifically, thedrive pin 17 of the output shaft 16 seats within the aligned slots 84 ofthe drive element 81, such that the rotational movement of the outputshaft 16 is transferred to the cutting element 33. Further, the drivepin 17 engages the spring 75 so as to axially bias the cutting element33 in the distal direction.

In operation, the distal end of the tool 10 is inserted into thesurgical site. The cutting element 33 is controlled by a control unit(not shown) connected to the handpiece cable 18, which control unitsupplies electrical power to the motor 15 of the handpiece 11 in orderto actuate the cutting element 33 and control the rotational speedthereof. If cutting of tissue is desired, then the motor 15 is activatedso as to cause the cutting element 33 to rotate within and relative tothe outer housing element 32, which effectively rotates the cutting head104 to allow the removal of tissue at the surgical site. In this regard,it will be appreciated that the control unit may include appropriatecontrol buttons so as to allow the surgeon or operator to select thedesired accessory operations. These control functions of the cuttingelement 33 may alternatively be performed directly from the handpiece 11which would then include the appropriate control buttons thereon.Alternatively, the control unit may be associated with a switch, eitherthrough a suitable cable or wirelessly, to allow the surgeon to operatethe controls remotely. Such a switch may be a footswitch or a handswitch.

As shown in FIGS. 9 and 10, with the cutting element 33 disposed withinthe housing element 32 and the accessory 12 secured to handpiece 11 asdescribed above, the cutting head 104 is positioned adjacent the window67 of the housing element 32 so that at least a portion of the cuttinghead 104 is exposed. In this regard, the cutting features of the cuttinghead 104 are shown herein as being covered on one side thereof by thedistal end 66 of the housing element 32. However, it will be appreciatedthat other configurations of the housing element distal end 66 may beprovided. For example, the housing tube 64 of the housing element 32 maybe provided with a length which allows full exposure of the cuttingfeatures of the cutting head 104 axially beyond the distal end 66 of thehousing tube 64, so that the cutting features of the cutting head 104are unhooded or uncovered completely.

The annular edge 68 of the housing tube 64, as shown in FIG. 11, isshaped so as to have a pair of opposed edges 70 which, when the cuttingelement 33 is assembled to the housing element 32 and is rotatedrelative thereto, act to clear surgical debris from the suction openings122 and 123 as discussed further below. The edges 70 may be providedwith a blunt or non-acute configuration, a chamfered configurationsuitable for cutting or resecting tissue, or a sharp or acuteconfiguration suitable for more aggressive tissue cutting.

If desirable or necessary, suction can be provided at the surgical siteby manipulating the valve 22 on the handpiece 11 to draw surgical debrisfrom the surgical site, first through the window 67 of the housingelement 32 and then through the suction openings 122 and 123. In thisregard, the axial location of the suction openings 122 and 123 along theneck portion 107, the size of the window 67 of the housing element 32and the distribution of the suction openings 122 and 123 about the neckportion 107 can be configured so that at least one of the suctionopenings 122 or 123 is located within the window 67 essentially at alltimes during rotation of the cutting element 33 relative to the housingelement 32. Surgical debris resulting from the cutting action of thecutting head 104 can be suctioned into the window 67 of the housingelement 32 and into an exposed suction opening 122 and/or 123, whichdebris is then suctioned into the suction passage 112 of the cuttinghead 104, into the drive shaft suction passage 89, into the handpiecesuction passage 20 and proximally through the handpiece 11 towards thesuction pump. The positioning of the suction openings 122 and 123 forcommunication with the window 67 and immediately proximate to thecutting features 114 of the cutting head 104 enables quick evacuation ofthe surgical debris from the surgical site.

In conventional cutting accessories, it is common for soft tissue tobecome wrapped around the cutting features, or an area just proximalthereof, during a surgical procedure, which in turn can cause cloggingof the suction opening located proximal to the cutting features asdiscussed above. However, because the suction openings 122 and 123 openoutwardly through the bearing surface 120 and the bearing surface 120 isradially spaced from the inner surface 121 of the housing tube 64 by arelatively small amount, soft tissue is prevented from wrapping aroundthe distal end 109 of the accessory 12 and clogging the suction openings122 and 123. Further, when the cutting element 33 is rotated within andrelative to the housing element 32, any tissue which is lodged orentangled within or adjacent the suction openings 122, 123 will be wipedaway or dislodged by the edge 70 of the window 67 of the outer housingelement 32 as the edge 132 or 130 of the suction opening 122 or 123rotates towards or approaches the adjacent edge 70 of the housing window67. When the inner cutting element 33 is rotated within and relative tothe outer housing element 32, the suction opening 123 (or the suctionopening 122) moves towards the stationary edge 70 of the window 67 ofthe outer housing tube 64. When the suction opening 123 (or the suctionopening 122) meets and moves past the edge 70, a wiping or cleaningaction will take place which, due to the close proximity (in the radialdirection) of the edge 70 to the suction opening, will serve to clearany accumulated tissue from the suction opening.

As discussed above, the edges 132 and 130 of the inner cutting element33 and/or the edges 70 of the outer housing element 32 may be configuredas cutting edges, which, in addition to the wiping action describedabove, provides a resection or cutting action at the suction openings122 and 123. Should tissue become lodged adjacent the window 67 during aprocedure, according to this embodiment, the tissue will be resectedbetween the respective edge 130, 132 of the suction opening 122 or 123and the edge 70 of the window 67 of the outer housing element 32, whichedges together create a scissoring action when the cutting element 33 isrotated relative to and within the housing element 32. Morespecifically, any tissue which is lodged within or adjacent the suctionopening 122 or 123 will be caught by the edge 132 or 130 of the suctionopening 122, 123 as same rotates towards the adjacent edge 70 of thehousing window 67, which effectively will server the tissue between thetwo edges (132 and 70, 130 and 70) and allow suction of the resectedtissue away from the surgical site.

The arrangement of the suction openings 122 and 123 on the bearingsurface 120 of the cutting head 104 can thus prevent, or at leastminimize, occlusion of the surgeon's field of view by surgical debrisdue to the wiping action performed by the edges 70 of the window 67 ofthe outer housing element 32 over the suction openings 122 and 123 assame rotate towards and past the adjacent edge 70 of the housing window67. Further, if the edges 130, 132 and/or 70 are configured as cuttingedges, tissue resection can additionally be carried out. Thisarrangement will prevent the surgeon from having to dismantle thesurgical accessory 12 from the handpiece 11 and remove the cuttingelement 33 from the housing element 32 in order to remove the tissuecausing the clog.

The window 67 of the outer housing tube 64 is sized, and the suctionopenings 122 and 123 are disposed in appropriate axial positions alongthe cutting head 104 of the drive shaft 88, so that the suction openings122, 123 are exposed (i.e. unblocked by the distal end 66 of the housingtube 64) through the housing window 67 along with at least a portion ofthe cutting head 104. In this regard, the suction openings 122, 123 willbe exposed to the surgical site through the window 67 when the suctionopenings 122, 123 are rotationally aligned with the window 67, and inthe illustrated embodiment at least two suction windows 122, 123 will beat least partially exposed at one time during rotation of the driveshaft 88. This arrangement allows the evacuation of surgical debristhrough the window 67 directly into the suction openings 122, 123.

Further, the suction openings 122, 123 are provided as separatestructures from the cutting head 104. That is, the suction openings 122,123 are not provided or defined in the cutting head 104, for example,between the cutting edges 114 or otherwise directly on the cutting head104. This arrangement is easier to manufacture and also allows thecutting head 104 to have a structure, when necessary or desirable, whichis sufficiently rigid to withstand aggressive cutting. While the suctionopenings 122, 123 are separate structures from the cutting head 104, thesuction openings 122, 123 are nonetheless positioned very close (in theaxial direction) to the cutting head 104 which results in more immediatesuctioning and thus removal of surgical debris. Additionally, the wipingaction of the edges 70 of the outer housing element window 67 over thesuction openings 122, 123 provides an efficient anti-clogging/cleaningmechanism. Also, in the embodiment wherein the suction opening edges 130and 132 and/or the edges 70 of the housing element window 67 areconfigured as cutting edges, the scissoring action between the edges130, 132 and the edges 70 allow for tissue resection adjacent the window70. Further, providing suction openings 122, 123 at varying axiallocations along the bearing surface 120 allows suction, and in theembodiment where the edges 130, 132 and/or edges 70 are configured ascutting edges, a cutting action, over an increased area (in the axialdirection) along the bearing surface 120. In some conventional burr-typesurgical accessories, the size of the suction openings or windows arenecessarily made large in an attempt to prevent clogging thereof. Theselarge-size suction openings or windows can cause the accessory to use alarge amount of saline or irrigating fluid during surgery and thus canresult in a high flow-rate. Since these accessories can extract moresaline than the inflow pump can provide, the pressure at the surgicalsite (such as in a bodily joint) can fall and potentially cause jointcollapse. For this reason, surgeons often keep the suction function ofthe accessory turned off and only occasionally turn same on to clear thefield of view at the surgical site. The suction openings 122 and 123 canbe made much smaller as compared to conventional accessories (in somecases 70% smaller than a conventional burr-type cutting accessory), dueto the cooperation between the suction openings 122, 123 and the housingwindow 67 as discussed herein, which provides an efficient cleaningmechanism for the suction openings 122, 123. The smaller size of thesuction openings 122, 123 results in reduced saline consumption andaccordingly reduces the possibility of joint collapse during surgery.Further, the surgeon is able to utilize and/or maintain suction throughthe accessory 12 during a cutting operation which will provide a betterfield of view of the surgical site during a cutting operation.

The bearing arrangement described herein includes the distal bearingdefined by the outer surface 120 of the inner cutting element 32 whichengages with the inner surface 121 of the housing tube 64 of the outerhousing element 32, and the proximal bearing defined by the engagementof the outer surface of the free end 61 of the housing tube 64 with theinner surface 74 of the hub 80 and the engagement of the terminal end 61of the housing tube 64 with the shoulder 71. With respect to theproximal bearing, the increased depth (in the axial direction) at whichthe housing tube 64 is bonded to the hub 34 of the housing element 32,resulting in the extension of the terminal end 61 of the housing tube 64into the bore 42 and beyond the shoulder 43, allows coupling orattachment of the hub 80 of the cutting element 33 to this terminal end61. This arrangement in effect allows the use of existing components,namely the housing tube 64 and the hub 80, to provide a proximal bearingsite, and the drive shaft 88/cutting head 104 and the inner surface 121of the housing tube 64 to provide a distal bearing site, and thusprovides bearings for the inner cutting element 33 at axially oppositeends of a very stiff housing tube 64. Due to the increased depth atwhich the housing tube 64 extends into the hub 34, the stiff housingtube 64 and the handpiece 11 overlap at the connection point between thetwo, i.e. adjacent the collet 26. This means that the tool 10 is stiffall of the way from the handpiece 11 to the distal end 109 of theaccessory 12, with very little stiffness lost at the connection betweenthe handpiece 11 and the accessory 12 at the collet 26, which provides amore rigid and stable tool 10. Further, the utilization of the hub 80 ofthe cutting element 33 and the free end 61 of the housing tube 64 asboth an axial and radial bearing lends stability to the accessory 12 atthe proximal end thereof and ensures that a radial gap is maintainedbetween the drive shaft 88 and the housing tube 64 at the proximal endof the accessory 12. In some conventional arrangements, a metal orlow-friction plastic spacer is used as an axial bearing between therotating hub of the inner cutting element and the hub of the outerhousing element. Thus, the utilization of existing components of theaccessory 12 to provide both axial and radial bearing support provides asimpler and more cost efficient arrangement.

In one embodiment, the wall 111 of the neck portion 107 of the cuttinghead 104 (which defines the outer surface 120) and the housing tube 64may be constructed of stainless steel coated with a low-friction andwear resistant material. This construction reduces wear during surgerywhich in turn reduces particle generation at the surgical site, andprovides hard, low-friction and corrosion-resistant surfaces. Someconventional surgical accessories utilize a metal-on-metal bearingarrangement at the distal end of the accessory wherein at least one ofthe bearing components is a separate component. Providing a bearing as aseparate component is necessarily more difficult and expensive tomanufacture. In contrast, the distal bearing arrangement is integratedinto existing components, resulting in a less expensive and simplerarrangement.

The cutting head 104, in the illustrated embodiment, can be provided asan integral structure which is machined from a single stainless steelbar stock to form the cutting edges 114, a larger diameter portion (theneck portion 107) proximal to the cutting edges 114 on which the outer(bearing) surface 120 is formed and the suction openings 122 and 123.The drive shaft 89 can be constructed of plastic and induction bonded tothe cutting head 104.

Utilizing a metal bearing surface, such as the surface 120 of thecutting head 104, which is machined during formation of the cutting head104, provides a repeatable and very stable bearing surface in closeproximity to the cutting features 114 of the cutting head 104. Thissurface 120 can be machined to very tight tolerances such that the gapbetween the outer diameter of the bearing surface 120 and the innerdiameter of the adjacent portion of the housing tube 64 can be kept verysmall and is easily repeatable during manufacture, meaning that the gapbetween the cutting edges 114 and the hood created by the distal end 66of the housing tube 64 (when the bur is of a hooded-type as in theillustrated embodiment), is repeatable. As a result of thisrepeatability in gap size between components, as well as the stablebearing arrangement in close proximity (in the axial direction) to thecutting features 114 of the cutting head 104, the accessory 12 is ableto withstand significantly more force (sideload) before the cuttingfeatures 114 will collide or make contact with the distal end 66 of thehousing tube 64, which can potentially cause metal debris to begenerated at the surgical site. The stable and low-friction bearingarrangement also means the accessory 12 is able to withstandsignificantly more force (sideload) before the drive shaft 88 makescontact with the housing tube 64, which can potentially cause stallingout or failure of the accessory.

FIGS. 12-21 illustrate additional embodiments of the surgical accessory12 which are substantially identical to the first embodiment of thesurgical accessory 33, except that these embodiments incorporatealternative configurations or geometries of the suction openingsprovided in the bearing surface of the inner cutting element of thesurgical accessory 12 as discussed below.

FIGS. 12 and 13 illustrate a second embodiment of the surgicalaccessory. Components of the second embodiment which are similar oridentical to components of the first embodiment of the surgicalaccessory 12 will include the same reference numbers as in the priorembodiment, plus “200”, and a detailed description of all componentswill accordingly not be provided. The surgical accessory 212 accordingto the second embodiment includes an inner cutting element 233 rotatablydisposed within an outer housing element 232. The inner cutting element233 incorporates a drive shaft assembly including a drive shaft 288having a distal end 291 with a cutting head 304. The tubular neckportion 307 of the cutting head 304 defines therein a plurality, andhere three, of suction openings 322 which open outwardly through thebearing surface 320 of the neck portion 307. These suction openings 322are substantially identical to one another and each has an elongatedconfiguration and extends in a helical manner about the longitudinalaxis 231 of the accessory 212 as the opening 322 projects longitudinallyalong the bearing surface 320. In the illustrated embodiment, thesuction openings 322 are uniformly circumferentially spaced from oneanother about the neck portion 307. Each of the suction openings 322extends completely through the wall 311 for communication with thesuction passage 312 of the cutting head 304 and the suction passage 289of the drive shaft 288. Each of the suction openings 322 has a pair ofopposed edges 332 disposed at the bearing surface 320.

The inner cutting element 233 is housed within the outer tubular housingelement 232 and the assembled accessory 212 is secured to the handpiece11 as in the prior embodiment. As shown in FIG. 13, with the cuttingelement 233 disposed within the outer housing element 232, the cuttinghead 304 and the bearing surface 320 are positioned adjacent the window267 of the housing element 232 so that at least a portion of the cuttinghead 304 and one or more of the suction windows 322 are exposed throughthe window 267. Further, with the cutting element 233 assembled to thehousing element 232, during use, the edges 270 of the housing tube 264act to wipe debris away from the suction openings 322 as the innercutting element 233 rotates within the outer housing element 232, as inthe prior embodiment. The edges 332 of the suction windows 322 and/orthe edges 270 of the housing tube 264 may be provided with edgessuitable for cutting/resecting tissue. In this embodiment, the cuttingedges 332 of the suction windows 322 cooperate with the edges 270 of thehousing tube 264 to cut or resect tissue as the cutting element 233rotates within the housing element 232 should this be necessary due to abuildup of surgical debris.

FIGS. 14 and 15 illustrate a third embodiment of the surgical accessory.Components of the third embodiment which are similar or identical tocomponents of the first embodiment of the surgical accessory 12 willinclude the same reference numbers as in the prior embodiment, plus“400”, and a detailed description of all components will therefore notbe provided. The surgical accessory 412 according to the secondembodiment includes an inner cutting element 433 rotatably disposedwithin an outer housing element 432. The inner cutting element 433incorporates a drive shaft assembly including a drive shaft 488 having adistal end 491 with a cutting head 504. The tubular neck portion 507 ofthe cutting head 504 defines therein a plurality, and here eight, ofsuction openings 522 which open outwardly through the bearing surface520 of the neck portion 507. These suction openings 522 aresubstantially identical to one another and each is configured as alongitudinally elongated slot which extends in a substantially linearmanner longitudinally along the bearing surface 520 substantiallyparallel to the axis 431 of the accessory 412. In the illustratedembodiment, the suction openings 522 are uniformly circumferentiallyspaced from one another about the neck portion 507. Each of the suctionopenings 522 extends completely through the wall 511 for communicationwith the suction passage 512 of the cutting head 504 and the suctionpassage 489 of the drive shaft 488. Each of the suction openings 522 hasa pair of opposed edges 532 disposed at the bearing surface 520.

The inner cutting element 433 is housed within the outer housing element432 and the assembled accessory 412 is secured to the handpiece 11. Asshown in FIG. 15, with the cutting element 433 disposed within the outerhousing element 432, the cutting head 504 and the bearing surface 520are positioned adjacent the window 467 of the housing element 432 sothat at least a portion of the cutting head 504 and one or more of thesuction openings 522 are exposed through the window 467. Further, withthe cutting element 433 assembled to the housing element 432, the edges470 of the housing tube 464 operate to wipe debris away from the suctionopenings 522. If the edges 532 of the suction openings 522 and/or theedges 470 of the housing tube 464 are configured as cutting edges, thenthe cutting edges 532 cooperate with the cutting edges 470 of thehousing tube 464 to cut tissue should this be necessary.

FIGS. 16-18 illustrate a fourth embodiment of the surgical accessory.Components of the fourth embodiment which are similar or identical tocomponents of the first embodiment of the surgical accessory 12 willinclude the same reference numbers as in the prior embodiment, plus“600”, and a detailed description of all components will not beprovided. The surgical accessory 612 according to the fourth embodimentincludes an inner cutting element 633 rotatably disposed within an outerhousing element 632. The inner cutting element 633 incorporates a driveshaft assembly including a drive shaft 688 having a distal end 691 witha cutting head 704. The tubular neck portion 707 of the cutting head 704defines therein a plurality, and here ten, of suction openings 722 whichopen outwardly through the bearing surface 720 of the neck portion 707.These suction openings 722 are substantially identical to one anotherand each is configured as a slot which is elongated in a directiontransverse to the axis 631. Each suction opening 722 has an arc lengthor a circumferential extent which is less than 180 degrees, and thesuction openings 722 are provided in diametrically opposed pairs in anaxial direction along the bearing surface 720 with the openings 722 ofeach opposed pair of openings being separated from one another by a pairof diametrically opposed bridge sections 729 of the wall 711 of the neckportion 607. In the illustrated embodiment, the bridge sections 729 ofeach pair of opposed suction openings 722 are circumferentially offsetfrom the respective bridge sections 729 of the axially-adjacent pair orpairs of opposed suction openings 722 by approximately ninety degrees.Further, the opposed pairs of suction openings 722 are spaced axiallyfrom one another in a substantially uniform manner along the bearingsurface 720. Each of the suction openings 722 extends completely throughthe wall 711 of the neck portion 707 for communication with the suctionpassage 712 of the cutting head 704 and the suction passage 689 of thedrive shaft 688. Further, each of the suction openings 722 has a pair ofopposed edges 732 disposed at the bearing surface 720.

The inner cutting element 633 is housed within the outer tubular housingelement 632 and the assembled accessory 612 is secured to the handpiece11. As shown in FIG. 18, with the cutting element 633 disposed withinthe outer housing element 632, the cutting head 704 and the bearingsurface 720 are positioned adjacent the window 667 of the housingelement 632 so that at least a portion of the cutting head 704 and oneor more of the suction openings 722 are exposed through the window 667.Further, with the cutting element 633 assembled to the housing element632, the edges 670 of the housing tube 664 wipe away debris from thesuction openings 722 as in the prior embodiments. If the edges 732 ofthe suction openings 722 and/or the edges 670 of the housing tube 664have cutting geometries, the cutting edges 732 of the suction openings722 cooperate with the cutting edges 670 of the housing tube 664 to cuttissue adjacent the cutting head 704.

FIGS. 19-21 illustrate a fifth embodiment of the surgical accessory.Components of the fifth embodiment which are similar or identical tocomponents of the first embodiment of the surgical accessory 12 willinclude the same reference numbers as in the prior embodiment, plus“800”, and a detailed description of all components will accordingly notbe provided. The surgical accessory 812 according to the fifthembodiment includes an inner cutting element 833 rotatably disposedwithin an outer housing element 832. The inner cutting element 833incorporates a drive shaft assembly including a drive shaft 888 having adistal end 891 with a cutting head 904. The tubular neck portion 907 ofthe cutting head 904 defines therein a plurality, and here four, ofsuction openings 922 and 923 disposed within the wall 911 which openoutwardly through the bearing surface 920 of the neck portion 907. Thesuction openings 922 and 923 are oriented in circumferentially spacedrelation with one another about the neck portion 907, and in theillustrated embodiment the suction openings 922 and 923 are spaced atapproximately 90 degree intervals from one another along thecircumference of the neck portion 907. Two of the suction openings 922are configured as longitudinally elongated holes and these suctionopenings 922 are diametrically opposed to one another (approximately 180degrees from one another) and are axially aligned with one another, andthe remaining two suction openings 923 are axially aligned with oneanother and are diametrically opposed one another on the neck portion907. The suction openings 923 in the illustrated embodiment areconfigured as circular holes. Each of the suction openings 922 and 923extends completely through the wall 911 for communication with thesuction passage 912 of the cutting head 904 and the suction passage 889of the drive shaft 888. Each suction opening 922 has a pair of opposededges 932 disposed at the bearing surface 920, and each suction opening923 has a pair of opposed edges 930 disposed at the bearing surface 920.In the illustrated embodiment, the suction openings 922, due to theirlongitudinally elongated shape, extend over a greater axial distancethan the suction openings 923.

The inner cutting element 833 is housed within the outer tubular housingelement 832 and the assembled accessory 812 is secured to the handpiece11. As shown in FIG. 21, with the cutting element 833 disposed withinthe outer housing element 832, the cutting head 904 and the bearingsurface 920 are positioned adjacent the window 867 of the housingelement 832 so that at least a portion of the cutting head 904 and oneor more of the suction openings 922 and 923 are exposed through thewindow 867. Further, with the cutting element 833 assembled to thehousing element 832, the edges 870 act to wipe away debris from thesuction openings 922 and 932. If the edges 932 and 930 and/or the edges870 of the housing tube 864 are configured as cutting edges, then thecutting edges 932 and 930 of the suction openings 922 and 923 cooperatewith the cutting edges 870 of the housing tube 864 to cut tissue shouldthis be necessary due to a buildup of surgical debris adjacent thecutting head 904.

FIGS. 22 and 23 illustrate a sixth embodiment of the surgical accessory.Components of the sixth embodiment which are similar or identical tocomponents of the first embodiment will include the same referencenumbers as in the first embodiment, plus “1000”, and a detaileddescription of all components will accordingly not be provided. Thesurgical accessory 1012 according to the sixth embodiment incorporatesan alternative configuration of the hub of the inner cutting elementwhich accommodates a larger diameter housing tube of the outer housingelement. In this regard, the hub 1080 of the inner cutting element 1033of this embodiment includes a substantially cylindrical protrusion 150which extends axially in the distal direction from the neck 1086 of thehub 1080 and has a smaller outer diameter than the outer diameter of theneck 1086. The neck 1086 and the protrusion 150 are joined to oneanother by a shoulder 1071 which faces in the distal direction andextends transversely relative to the axis 1031 between the protrusion150 and the neck 1086. The hub bore 1087 in this embodiment has asubstantially constant inner diameter and opens proximally through thedrive element 1081 and distally through the protrusion 150. As bestshown in FIG. 23, the protrusion 150 has an outer surface 151 whichdefines therein a pair longitudinally extending chamfers or flats 152which extend from the distal terminal end of the protrusion 150 to thehead 1086. Further, the head 1086 defines therein a pair of transverselyextending channels 153 which extend radially outwardly from respectiveinner ends of the flats 152 and open radially through the head 1086.

The housing tube 1064 of the outer housing element 1032 in thisembodiment, as in the first embodiment, has a proximal end 1060 which isinduction bonded to the hub 1034, which hub 1034 has a large inductioncore through which the proximal end 1060 extends via the bore 1041. Theproximal end 1060 extends in the proximal direction axially beyond theshoulder 1043 of the hub 1034 so as to have an exposed free end 1061which extends over the outer surface 151 of the protrusion 150 of thehub 1080 of the inner cutting element 1033.

When the cutting element 1033 is fully inserted into housing element1032, the free end 1061 of the housing tube 1064 extends over theprotrusion 150 like a sleeve, and the free terminal end 1061 of thehousing tube 1064 abuts axially against the shoulder 1071, as shown inFIG. 22. The outer diameter of the outer surface 151 of the protrusion150 is slightly smaller than the inner diameter of the free end 1061 soas to allow the insertion of the protrusion 150 thereinto and such thatthere is only a small radial clearance between the inner surface of thefree end 1061 and the outer surface 151. The radial engagement of theouter surface 151 with the inner surface of the free end 1061 of thehousing tube 1064 and the axial engagement of the free terminal end 1061of the housing tube 1064 with the shoulder 1071 provides both a radialbearing and an axial bearing, respectively, at the proximal end of thesurgical accessory 1012. When the accessory 1012 is mounted to thehandpiece 11, a spring (not shown here, but similar to the spring 75)provided within the drive element 1081 of the cutting element 1033cooperates with the handpiece 11 and biases the cutting element 1033 inthe distal direction relative to the outer housing element 1032, whichserves to maintain the free or terminal end 1061 of the housing tube1064 against the shoulder 1071. The mating areas between the innersurface of the free end 1061 of the housing tube 1064 and the outersurface 151 of the protrusion 150 can be provided with lubricant inorder to minimize friction between these components during movement ofthe inner cutting element 1033 relative to the outer housing element1032. In this regard, lubricant can be applied to the flats 152 and/orthe channels 153 so as to lubricate the areas between the housing tube1064 and the hub 1080.

Although particular preferred embodiments of the invention are disclosedin detail for illustrative purposes, it will be recognized thatvariations or modifications of the disclosed apparatus, including therearrangement of parts, lie within the scope of the present invention.

What is claimed is:
 1. Surgical cutting accessory comprising: a housingelement including a hub and a housing tube projecting distally from saidhub and being formed by a generally tubular wall defining an interior ofsaid housing tube, said housing tube having a proximal end and a distalend spaced from said proximal end, said distal end defining a windowtherein; a cutting element including a hub and a shaft fixed to andprojecting distally from said hub of said cutting element, said shaftbeing disposed within said interior of said housing tube for rotationalmovement relative thereto, said shaft having a distal end including acutting head which defines a tissue-cutting feature thereon, said distalend of said shaft having a portion disposed proximally of saidtissue-cutting feature, said portion defining an outer bearing surfacehaving an outer diameter slightly less than an inner diameter of anadjacent inner surface of said tubular wall of said housing tube at saiddistal end thereof, said outer bearing surface and said inner surface ofsaid housing tube together forming a distal bearing for supporting saiddistal end of said shaft relative to said distal end of said housingtube, said window of said housing tube being sized to expose a portionof said cutting feature of said cutting head, said proximal end of saidhousing tube projecting in a proximal direction from said hub of saidhousing element for cooperation with a surface of said hub of saidcutting element, said proximal end of said housing tube and said surfaceof said hub of said cutting element together forming a proximal bearingfor supporting a proximal end of said shaft relative to said housingelement.
 2. The accessory of claim 1, wherein said proximal end of saidshaft defines a longitudinal axis, and said surface of said hub of saidcutting element is oriented transversely relative to the axis, saidproximal end of said housing tube being disposed to abut said surface inthe axial direction to form an axial bearing.
 3. The accessory of claim1, wherein said proximal end of said shaft defines a longitudinal axis,and said surface of said hub of said cutting element is orientedaxially, said proximal end of said housing tube having an outer surfaceengaged with said surface of said hub of said cutting element to form aradial bearing, or an inner surface engaged with said surface of saidhub of said cutting element to form a radial bearing.
 4. The accessoryof claim 1, wherein said proximal end of said shaft defines alongitudinal axis, said surface of said hub of said cutting element is afirst surface and said hub of said cutting element has a second surface,said first surface being oriented transversely relative to the axis andsaid proximal end of said housing tube being disposed to abut saidsurface in the axial direction to form an axial bearing of said proximalbearing, said second surface being oriented axially and engaging witheither an outer surface of said proximal end of said housing tube or aninner surface of said proximal end of said housing tube, to form aradial bearing of said proximal bearing.
 5. The accessory of claim 1,wherein said portion of said distal end of said cutting element definestherein a suction opening disposed closely axially adjacent said cuttingfeature and opening outwardly through said outer bearing surface andcommunicating with a hollow interior of said cutting element and asuction source, said window of said housing element having an outerperimeter sized to expose both said portion of said cutting feature anda substantial portion of said suction opening at least during rotationof said cutting element relative to said housing element.
 6. Theaccessory of claim 5, wherein said distal end of said cutting elementdefines a longitudinal axis and said window opens in a directiontransverse to the axis, said window being partially defined by an edgeformed on said wall of said housing element and disposed axiallyadjacent to said suction opening, said shaft being disposed for rotatingmovement within said interior of said housing tube to move said suctionopening towards said edge of said window of said housing element toclear away tissue adjacent said suction opening.
 7. The accessory ofclaim 6, wherein said outer bearing surface and said suction opening aredisposed closely radially adjacent to, and have a configuration whichsubstantially conforms to, said inner surface of said housing tube. 8.The accessory of claim 6, wherein said edge which partially defines saidwindow is configured as a cutting edge to cut tissue, and said portionof said cutting element has an edge which partially defines said suctionopening and is configured as a cutting edge to cut tissue, said cuttingedge of said suction opening being disposed in opposed relation withsaid cutting edge of said window, and said shaft when rotated moves saidcutting edge of said suction opening towards said cutting edge of saidwindow to cut tissue adjacent said window.
 9. The accessory of claim 1,wherein said distal end of said cutting element defines a longitudinalaxis and a plurality of suction openings are defined in said portionclosely axially adjacent said cutting feature and open outwardly throughsaid outer bearing surface and communicate with a hollow interior ofsaid cutting element and a suction source, some of said suction openingsbeing disposed in said outer bearing surface at different axialpositions therealong.
 10. The accessory of claim 1, wherein said distalend of said cutting element defines a longitudinal axis and a pluralityof suction openings are defined in said portion closely axially adjacentsaid cutting feature and open outwardly through said outer bearingsurface and communicate with a hollow interior of said cutting elementand a suction source, said suction openings being configured as one of:elongated slots which extend substantially helically along said outerbearing surface; elongated slots which extend substantially linearlyalong said outer bearing surface and substantially parallel to the axis;and elongated slots which extend along said outer bearing surfacetransversely to the axis.
 11. A surgical cutting accessory for use witha powered surgical handpiece, said accessory comprising an outer housingelement having a proximal end and a distal end spaced therefrom andformed from a generally tubular wall, said distal end defining an axis,said accessory further including an inner cutting element disposedwithin said outer housing element for rotation relative thereto, saidwall of said outer housing element defining therein a window at saiddistal end, said inner cutting element having a distal end including acutting head which defines a cutting feature thereon, said distal end ofsaid inner cutting element having a portion formed from a generallytubular wall, said inner cutting element including a suction openingdisposed in said wall of said inner cutting element closely axiallyadjacent said cutting feature, said suction opening communicating with ahollow interior of said inner cutting element and a suction source, saidsuction opening being partially defined by a cutting edge formed on saidwall of said distal end of said inner cutting element, said window beingpartially defined by a cutting edge formed on said wall of said distalend of said outer housing element, said cutting edge of said suctionopening being disposed axially adjacent to said cutting edge of saidwindow, said window having a perimeter sized to expose a portion of saidcutting feature, said suction opening and said cutting edge thereofbeing at least partially exposed through said window at least duringrotation of said inner cutting element.
 12. The accessory of claim 11,wherein said wall of said distal end of said outer housing elementdefines an inner surface and said wall of said distal end of said innercutting element defines an outer surface disposed closely adjacent to,and having a configuration substantially conforming to, said innersurface, said inner and outer surfaces being disposed in bearing contactwith one another, said suction opening and said cutting edge thereofbeing disposed in said outer surface for cooperation with said cuttingedge of said window of said outer housing element during rotation ofsaid inner cutting element.
 13. The accessory of claim 11, wherein saidcutting head comprises a bur including a plurality of cutting edgesextending generally axially along said bur.
 14. The accessory of claim13, wherein said plurality of cutting edges extend generally helicallyabout the axis.
 15. The accessory of claim 11, wherein said cutting headof said inner cutting element comprises a bur defining said cutting edgethereon, said bur being of a solid configuration with said suctionopening being disposed axially adjacent and proximally of said bur, andbeing separate from said bur.
 16. The accessory of claim 15, whereinsaid cutting head, said suction opening and said cutting edge thereofare all axially aligned with said window.
 17. The accessory of claim 11,wherein said inner cutting element includes a plurality of said suctionopenings disposed in said wall of said distal end of said inner cuttingelement closely axially adjacent said cutting feature, each said suctionopening communicating with said hollow interior of said inner cuttingelement and a suction source, each said suction opening being partiallydefined by a cutting edge formed on said wall of said distal end of saidinner cutting element, and each said suction opening being at leastpartially exposed through said perimeter of said window of said outerhousing element during rotation of said inner cutting element.
 18. Theaccessory of claim 17, wherein said plurality of said suction openingsare disposed at different axial locations along said distal end of saidinner cutting element.
 19. The accessory of claim 11, wherein said innercutting element includes a hub defining a proximal end of said innercutting element and a shaft joined to and projecting distally from saidhub and defining said wall of said inner cutting element, said shaftdefining an outer bearing surface thereon having an outer diametersimilar to but less than an inner diameter of said wall of said outerhousing element adjacent said window to define a distal bearing forsupporting said inner cutting element during rotation relative to andwithin said outer housing element.
 20. The accessory of claim 19,wherein said outer housing element includes a hub defining said proximalend of said outer housing element and a housing tube fixed to andprojecting distally from said hub of said outer housing element anddefining said wall thereof, said housing tube having a proximal endspaced from said window and projecting in a proximal direction forcooperation with a surface of said hub of said inner cutting element,said proximal end of said housing tube and said surface of said hub ofsaid inner cutting element together forming a proximal bearing forsupporting said inner cutting element during rotation relative to andwithin said outer housing element.